IP Law Daily Validity of patents for RA treatment drug Enbrel affirmed
Monday, July 6, 2020

Validity of patents for RA treatment drug Enbrel affirmed

By George Basharis, J.D.

Patents for the blockbuster drug Enbrel used to treat rheumatoid arthritis were not invalid.

The federal district court in New Jersey did not err in ruling that patents covering Immunex Corporation’s immunosuppressant Enbrel were not invalid based on challenges for lack of obviousness-type double patenting, written description, or obviousness, a divided panel of the U.S. Court of Appeals for the Federal Circuit has held. The agreement granting Immunex an exclusive license to use the patents for the active ingredient in Enbrel did not transfer all substantial rights to Immunex and, therefore, Immunex’s expired patents and the patents subject to the license agreement did not have common ownership. The Federal Circuit also affirmed the lower court’s findings that the patent specifications satisfied the written description requirement and that simultaneous invention did not support obviousness (Immunex Corp. v. Sandoz Inc., July 1, 2020, O'Malley, K.).

Immunex owns the biologic drug, Enbrel, which is used primarily to treat rheumatoid arthritis. The active ingredient of Enbrel is the fusion protein etanercept. Hoffman-La Roche, Inc. (Roche) owns U.S. Patent No. 8,063,182 (the ’182 Patent), related to etanercept, and U.S. Patent No. 8,163,522 (the ’522 Patent), related to methods of making etanercept. Immunex has exclusive licenses to the ’182 and ’522 Patents.

Sandoz Inc. filed an application for approval to market a biosimilar version of Enbrel, Erelzi. Immunex responded to the application by filing a patent infringement suit. Sandoz did not contest infringement but argued instead that the ’182 and ’522 Patents were invalid for obviousness-type double patenting, failure to meet the written description requirement, and obviousness. The district court ruled in favor of Immunex, finding that Sandoz had failed to prove that the patents were invalid.

Obviousness-type double patenting. The purpose of the rule against double patenting is to prevent an inventor from effectively extending the term of exclusivity by the subsequent patents of variations that are not patentable distinct from the first-patented invention. Sandoz argued that the ’182 and ’522 Patents were invalid because the rights acquired to the patents by Immunex were the same as Immunex’s expired etanercept patents. To determine the validity of the patents, the Federal Circuit applied the "substantial rights test." Sandoz maintained that the license agreement transferred all substantial rights to Immunex because Immunex had the right to sue to enforce the patents. However, Immunex only had a first right to sue. Roche retained a secondary right of enforcement, and Immunex had a duty to cooperate with Roche. Further, the agreement gave Roche the right to veto any proposed assignment of the patents to unrelated parties. The Federal Circuit held that the enforcement and alienation rights retained by Roche made clear that the agreement did not transfer all substantial rights in the patents to Immunex. Consequently, the ’182 and ’522 Patents were not commonly owned with Immunex’s expired patents.

Written description. The district court determined that the priority application for the ’182 and ’522 Patents included written description support for the claimed invention. It rejected Sandoz’s argument that the patents were invalid because the claimed invention could only be found by going outside the specification. The Federal Circuit agreed, noting that it was "well-established that a patent specification need not re-describe known prior art concepts." Given the prior art, a person of ordinary skill in the art would have arrived at the claimed invention by reading the specification, the court said.

Obviousness. The lower court’s rejection of Sandoz’s obviousness challenge was not clearly erroneous, the Federal Circuit determined. The district court properly weighed the evidence and concluded that the prior art would not have motivated a person of ordinary skill in the art to select the individual component of etanercept. There was ample support in the record for the court’s conclusion that it would not have been obvious to a person of ordinary skill in the art to combine the prior art references. The district court’s analysis of objective indicia of non-obviousness also was not clearly erroneous, the Federal Circuit determined.

Dissenting opinion. In a dissenting opinion, Circuit Judge Jimmy Reyna argued that in applying the "substantial rights test," the majority should have found that the ’182 and ’522 Patents were commonly owned with Immunex’s expired patents. According to Judge Reyna, Roche’s secondary right to sue and its right to veto an Immunex-initiated assignment were "illusory" because the retained rights did not prevent Immunex from enjoying the ’182 and ’522 Patents in any meaningful way. Immunex could nullify Roche’s anti-alienation rights by paying it a de minimis amount of $50,000 and leaving Roche without any rights at all in the patents. Immunex could also nullify Roche’s secondary right to sue by issuing a royalty-free sublicense to the alleged infringer. Thus, Immunex retained full control over whether Roche could initiate suit. Finally, although not addressed by the majority, Judge Reyna found that the district court applied the wrong test to determine that the ’182 and ’522 Patents were patentably indistinct from Immunex’s expired patents.

This case is No. 20-1037.

Attorneys: Constantine L. Trela, Jr. (Sidley Austin LLP) for Immunex Corp. and Amgen Manufacturing, Ltd. William M. Jay (Goodwin Procter LLP) for Sandoz Inc., Sandoz International GmbH and Sandoz GmbH.

Companies: Immunex Corp.; Amgen Manufacturing, Ltd.; Sandoz Inc.; Sandoz International GmbH; Sandoz GmbH

MainStory: TopStory Patent GCNNews FedCirNews

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